1. Field of the Invention
The present invention relates to a booster circuit.
2. Description of the Prior Art
In order to drive a liquid crystal display device incorporated in a desktop computer or in a pocket-size calculator, a power source must supply a voltage of the order of 4.5 to 10 V. In general the desktop computers and pocket-size calculators operate on one or two mercury or silver oxide batteries (1.5 V to 3.0 V) so that a booster or step-up circuit must be provided in order to drive the liquid crystal display device.
To this end DC-DC converters including a boosting transformer have been used, but their energy transfer efficiency is considerably low as their power consumption is as much as or exceeds the power consumption in a load or a liquid crystal display device. Furthermore the DC-DC converter represents a considerable part of the cost of the desktop computer or the pocket-size calculator so that the cost of the DC converter must be reduced in order to reduce the total cost of the calculator.